Income Taxes - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2018 subsidiary
Income Tax [Line Items]
Tax benefit related to remeasurment of deferred tax balance and valuation allowance | $	$ 8,606
Extra Space Management, Inc
Income Tax [Line Items]
Number of taxable REIT subsidiaries | subsidiary		1